With increasing integration of integrated circuits, electronic devices such as power adapters and power supply apparatuses are developed toward minimization. As the volume of the electronic device is decreased, the problem associated with heat dissipation becomes more serious. Take a power adapter for example. The conventional power adapter comprises an upper housing and a lower housing, which are made of plastic materials and cooperatively define a closed space for accommodating a printed circuit board. When the power adapter operates, the electronic components (e.g. transistors) on the printed circuit board may generate energy in the form of heat, which is readily accumulated within the closed space and usually difficult to dissipate away. If the power adapter fails to transfer enough heat to ambient air, the elevated operating temperature may result in damage of the electronic components, a breakdown of the whole power adapter or reduced power conversion efficiency.
For removing the heat generated from the electronic device to the ambient air, the electronic device is usually provided with an active heat-dissipation mechanism. The active heat-dissipation mechanism uses an external driving device (e.g. a fan) to inhale the external cooling air to cool the electronic components or exhaust the hot air inside the housing to the ambient air. For example, an air-intake type axial flow fan is usually disposed on a surface of the housing of the electronic device for introducing airflow into the inner portion of the electronic device and then exhausting the hot airflow through an opposite surface of the housing.
The conventional active heat-dissipation mechanism, however, still has some drawbacks. For example, since the airflow fails to be centralized to pass through the higher power component, the heat-dissipating efficiency is usually unsatisfied. In addition, the electronic components arranged at the downstream of the airflow path are usually suffered from a heat pollution problem. Under this circumstance, the heat generated from these electronic components fails to be uniformly dissipated. Moreover, the use of the fan generates undesired noise.
There is a need of providing an airflow-adjustable active heat-dissipation mechanism of an electronic device to obviate the drawbacks encountered from the prior art.